Study of hydrogenation versus de-loading of Co and Mn doped ZnO semiconductor

▶ H-induced ferromagnetism in Co-doped ZnO vanishes upon its re-heating/ long storage. ▶ “Switch” action of ferromagnetism between hydrogenation and re-heating in ZnO:CO. ▶ ZnO:Co shows giant ferromagnetism on H-injection, in contrast, the ZnO:Mn does not! ▶Ferromagnetism show close relation with oxygen vacancies in magnetic semiconductors.